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    <title>Document</title>
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    <script>
        /**
         *  预解析[变量提声]:
         * 
         */

        var a = 10;
        var d = 40;
        function fn(a,b){
            console.log(a);
            console.log(c);
            f1();
            var c = 30;
            a = 100;
            b = 20;
            d = 50;
            console.log(a,b,c,d);
            function f1(){
                console.log('f1被调用了')
            }
        }
        fn(11,22);
        console.log(a);
        console.log(d);
    </script>
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